Browsing by Author "Upadhyaya, MK."

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Effects of moisture loss on water potential components and tissue deterioration in carrots during Short-term storage
(American society for horticultural science, 1995-07-01) Shibairo, Solomon I.; Upadhyaya, MK.; Toivonen, PMA.
Studies were carried out to understand the effects of moisture loss on water potential and root deterioration in carrot (Daucus carota L. `Eagle') roots during short-term storage. The roots were stored at various temperatures and relative humidities (RH) to provide 0.7 (low), 3 (medium), and 9 mbars (high) of water vapor pressure deficit (WVPD). Carrots at high WVPD lost the most weight, followed by those at medium and lowest WVPD. Water potential and osmotic potential of the carrot tissue at high WVPD did not change significantly up to 6 days, but decreased thereafter. There was no change in water potential and osmotic potential for carrots at medium and low WVPD. A significant quadratic relationship (P = 0.05, r = –0.764) between water potential and carrot root weight loss was observed. Relative electrolyte leakage increased over time in carrots at the high WVPD.
Influence of preharvest water stress on postharvest weight loss of carrots (Daucus carota L.)
(American society for horticultural science, 1996-08-01) Upadhyaya, MK.; Shibairo, Solomon I.; Toivonen, PMA.
To understand the relationship between preharvest water stress and postharvest moisture loss, carrot cvs Eagle and Paramount were grown in muck soil in 6 1 pots (eight carrots per pot) in a greenhouse at the University of British Columbia. The plants were watered to field capacity every second day for 5.5 months prior to receiving 100,75,50 and 25% field capacity water stress treatments (for 4.5 weeks), henceforth referred to as low, medium, high and severe water stress respectively. Postharvest moisture loss of carrots stored at 13μC and 32% relative humidity was monitored every second day for three weeks. The percent moisture loss was low in the low water stressed, and high in the severely water stressed carrots of both cultivars. Root crown diameter, weight, and water and osmotic potentials decreased, whereas specific surface area and relative solute leakage increased with increasing preharvest water stress. The results show that carrots adjust to water stress by lowering water and osmotic potentials. Root water potential, followed by relative solute leakage, were the variables which accounted for most of the variation in moisture loss. It is suggested that preharvest water stress lowers membrane integrity of carrot roots, and this may enhance moisture loss during storage.
Potassium nutrition and shelf life of carrots (Daucus carota L.)
(American society for horticultural science, 1996-08-01) Shibairo, Solomon I.; Upadhyaya, MK.; Toivonen, PMA.
The effect of potassium (K) nutrition on the shelf life of carrots was studied using a hydroponics system involving rockwool slabs as support. Carrots were grown for 192 days under greenhouse conditions and supplied with 0, 0.1, 1.0, 10, and 15 mm of K. Increase in K concentration in the nutrient medium decreased postharvest weight loss. Carrot weight and tissue K content increased and water potential, osmotic potential, and relative solute leakage decreased with increasing K concentration in the nutrient feed. Differences in postharvest weight loss were mainly associated to root weight and relative solute leakage. Root weight correlated negatively and relative solute leakage correlated positively to water loss. Water and osmotic potential also correlated to water loss, but not as strongly as root weight and relative solute leakage.
Replacement of postharvest moisture loss by recharging and its effect on subsequent moisture loss during short-term storage of carrots (Daucus carota L.)
(American society for horticultural science, 1997-06-01) Upadhyaya, MK.; Shibairo, Solomon I.; Toivonen, PMA.
The replacement of postharvest moisture loss in carrots (cv. Caro-choice) by single and repeated recharging (i.e., rehydration in water) treatments, interaction between the duration of recharging and temperature during recharging, and the effects of these treatments on moisture loss during subsequent short-term storage were studied. Carrot weight gain increased with increase in the duration of single recharging treatments. Carrots that had lost 2.96% of their weight, during storage at 13°C and 35% relative humidity, regained as much as 2.45% of the weight during recharging for 12 h. Longer rechargings had little additional effect. Recharging at 13°C and 26°C was more effective at replacing water than at 0°C. The rate of moisture loss (%/day) during subsequent storage was not affected by recharging duration and the temperature. With repeated recharging (every 3.5 d), increase in recharging duration up to 9 h …